Influencing Factors Analysis on Sunken Greenbelt Design of Urban Road

In order to provide scientific basis for the design parameters’ selection of sunken greenbelt of urban road, computational formulae of critical sunken depth and sunken greenbelt plant’s submergence time were derived based on the storage-infiltration analysis of sunken greenbelt. And then the influence of various factors on the sunken greenbelt design of urban road were computed and analyzed. Results show that: soil infiltration coefficient, design recurrence interval of storm and sunken greenbelt plant’s submergence time are the key influencing factors on the sunken greenbelt design. Under the same condition, critical sunken depth decreases linearly with the increase of soil infiltration coefficient, and increases nonlinearly with the increase of design recurrence interval of storm. Sunken greenbelt plant’s submergence time is proportional to sunken depth of sunken greenbelt, and it is inversely proportional to soil infiltration coefficient. When the value of soil infiltration coefficient is greater than 10-6 m/s and the sunken depth range from 0 to 0.25 meters, submergence time of sunken greenbelt plants is all within 70h, and the sunken greenbelt can most infiltrate the rainfall storage in 1d. Considering all the influencing factors, soil infiltration coefficient of sunken greenbelt of urban road should be greater than10-6 m/s and the appropriate sunken depth should be range from 0 to 0.25 meters.